Explanation:
Atomic number of hydrogen is 1 and its electronic configuration is 
. So, in order to attain stability it needs to gain one more electron from another atom.
As helium cannot donate its one valence electron because if it does so then there will be no electron present in a hydrogen atom which is not possible. Therefore, it needs to share its valence electron with another atom.
A chemical bond formed by sharing of electrons is known as a covalent bond. So, hydrogen atom always shares its valence electron and hence, it always forms a covalent bond.
On the other hand, atomic number of helium is 2 and its electronic configuration is 
.
Since, helium atom has completely fill orbital so, it is stable in nature. Therefore, it will neither gain or lose electrons under normal conditions.
As a result, helium will not form a covalent bond.
Answer:
sorry but i'm not that smart
<h3>Answer:</h3>
221.90 g.mol⁻¹
<h3>Explanation:</h3>
The mass of contained by a molecule is known as molecular mass. It is the sum of atomic weights of the elements contained by the molecule. In given case Iodine Pentafluoride has a chemical formula,
IF₅
The atomic weights of each element are as;
Iodine = 126.90 g.mol⁻¹
Fluorine = 19.00 g.mol⁻¹
As there are five atoms of Fluorine so, we will multiply the atomic weight of Fluorine by five and that of Iodine by one as there is only one Iodine atom.
Therefore,
Molecular Mass of IF₅ = (1 × 126.90 g.mol⁻¹) + (5 × 19.00 g.mol⁻¹)
Molecular Mass of IF₅ = (126.90 g.mol⁻¹) + (95.00 g.mol⁻¹)
Molecular Mass of IF₅ = 221.90 g.mol⁻¹
An ionic bond forms between a metal and a nonmetal. So, since C and O are nonmetals it cannot be that one. Also, P and Cl are also both nonmetals so it cannot be that one either. That leaves Li and O and Ca and Br. In an ionic bond metals loose electrons and nonmetals gain electrons. Therefore it cannot be Li and O because it states that oxygen, the nonmetal, looses electrons and lithium, the metal, looses electrons. So, the answer has to be Ca and Br because Ca, the metal, looses electrons and Br, the nonmetal, gains electrons.
Answer:
C.11
Explanation:
Boron-11 makes up around 80% of all natural Boron. And, typically, the quickest way to determine the most abundant isotope of an element is to just round the atomic mass to the nearest whole number.
